1. Field of the Invention
This invention relates to storage units, such as wheeled trailers and, more particularly, to a load beam assembly that is operably mounted within a space defined by such a storage unit to define a cargo support above a floor on the storage unit.
2. Background Art
It is known to utilize load beams in storage spaces in trailers on commercial vehicles to provide an additional support level for cargo between the floor and roof bounding such cargo spaces. An exemplary structure is shown in U.S. Pat. No. 6,364,583 (the '583 patent). The '583 patent discloses a load beam assembly of the type that is utilized in a commercial system identified by the owner herein as its “Lift-A-Deck” system.
With the load beam assembly in the '583 patent, substantial flexibility is afforded in terms of varying the height and front-to-rear location of one or more load beams. Cargo can be spanned directly across two or more of such load beams or, alternatively, elongate supporting components may bridge adjacent load beams to cooperatively produce a stable subjacent support surface for cargo. The latter arrangement potentially reduces the number of load beams that must be utilized and has particular utility for cargo with a smaller footprint and that which needs a more significant contact area to be stably supported in the space.
There are a number of objectives that guide designers of these load beams. Most significantly, the load beams must have adequate structural integrity so that they do not fail in what is often a demanding environment, particularly where the cargo is heavy. Over-the-road vehicles cause loaded cargo to be subjected to large forces that tend to cause shifting of the cargo. This shifting may cause cargo to be damaged or, in a worst case, interfere with vehicle operation. This problem is particularly prevalent in trailers that are only partially filled so that there is a substantial amount of empty space into which the cargo might shift.
It is also desirable to minimize the size of the load beams. Space in commercial vehicles is at a premium and it is thus important that this space be optimally utilized without sacrificing the integrity of the load beams.
Weight is also a significant consideration in the design of such load beams. Added weight translates into decreased fuel mileage. Reduced fuel mileage results in lost profit or necessitates raising of transportation rates, which has an obvious downside.
As noted above, designers must always balance the advantages associated with reducing size and weight against any compromising of structural integrity that results therefrom.
Another drawback with size reduction is that while size reduction may not ultimately significantly affect integrity, it may affect the operation of the load beams. For example, load beams narrowed to reduce dimension and weight may afford a significantly smaller contact area for supported cargo. There may be an increased risk that cargo may shift off of this reduced width load beam. Further, width reduction may occur to the point that the upper surfaces of the load beams cause a localized stress upon the underside of the cargo that they support, potentially causing either damage or inhibiting movement of the cargo during loading and/or loading thereof.
One devised design developed to address the above problems utilizes a “T”-shaped cross-sectional beam construction as shown in FIG. 5 in the '583 patent and also in EP 0 620 148 B1 (“EP '148”).
In EP '148, the cross bar of the “T” defines an upwardly facing support surface that is rectangular in shape, as viewed in plan. This configuration produces sharp corners at the beam ends that might contact the individuals handling, or working around, the beams during: a) movement of the beams into and out of the storage spaces; b) setup of the beams within the storage spaces; and c) other handling of the beams, such as when they are otherwise moved or transported. These potentially sharp regions remain exposed with the beams operatively in place. Thus, there is an ongoing potential for those handling and working around the beams to be contacted, as during cargo loading and unloading, in a manner whereby there is the potential for injury.
Additionally, the exposed sharp regions produced by the beam configuration may cause damage to cargo that comes in contact with the beams as the cargo is loaded, unloaded, and potentially shifts once in a loaded state.
The industry continues to seek out designs of load beams that have excellent performance characteristics and integrity, while at the same time being relatively light in weight and of an unobtrusive size.